rushmore



July 13 1926.

Re. 16,382` s. W. RUSHMRE RADIATOR Fon COOLING FLUIDs original Filed De e. 1921 3 sheets-sheet 1 mm mmmmll HMMHHH l 1921 3 Sheets-Sheet 2 S. W. RUSHMORE RADIATOR FOR COOLING FLUIDS Original Filed DSC. G.

July 13 v1926.

. 71515lill/541141,51!.

Re, 16,382 s w RUSHMORE RADuToR Foa coouue FLUIDs original Filed Dc. e. 1921 s sheets-sheet g nomtoz ,bmue///fus/mv Sg? la@ btowu;

July 13 1926.

'Re-awed July 13, 192e.

UNITED STATES Re. 16,382 PATENT OFFICE.

SAMUEL W. BUSHIOBE, F PLAINFIELD, NEW JERSEY.

RADIATOR FOR COOLING FLUIDS.

'originar no. 1,455,739, dated :my 15, 192s, serial no. 520,210, mea December e, 1921. application for reissue illed Hay 6, 1925. Serial 28,516.

My present invention relates to radiators,

particularly radiators for use with cooling.

systems of the type which operate by the boiling and condensing cycle for the cooll ing of automotive engines.

In the system described in my Patent No. 1,378,724, granted May 17, 1921, the water and steam from the engine jacket is disv charged into a separating chamber in the bottom of the radiator, the water being returned to the engine jacket and the steam rising into the air-cooled passages of the vradiator, so that the radiator operates as an up-ow condenser, the condensate returning by gravity against the upward flow of steam.

In said patent this method is referred to as applicable to radiators of the types which are now employed as standard equipment on 5 automobiles. trucks, etc., but such radiators are primarily designedv for. cooling of water instead of steam, by down-flow instead of upow, and I have discovered that in the practical operation of such radiators bythe 95 steam cooling system, ythe potential cooling vcapacity is not fully utilized.

The primaryl dii'culty is that the fan which draws the cooling air through the radiator, induces a much heavier blast in the i 3 central portions of the condensing area than at the sides. Consequently the central portions are capable of radiating much more heat and condensing much more steam per unit of cooling surface, than are the sides. But the side passages which are least cool are designed to have the same or less. flow resistance than the central portions. with the result that where the relatively frictionless, massless steam is swstituted for water. the balance between the several up and down passages, as'regardsow-capacity and conden'sation capacity, is completely upset.

Careful experiment shows that long before the total volume of steam to be condensed becomes great enough to tax the cooling capacity of the radiator as a whole` the inferior cooling capacity at the sides will 'be over'taxes. The heat therefore creeps lhigher up,heating theside portions: the air becomes lighter so that the hot air and steam rise up into the empty space at the top of the radiator displacing the colder air downward `(because the colder air-is heavier and because air, even at 212 F., is about 60% heavier than steam); but the same or even lcludes proportioning and yarranging the greater volume of steam flowing directly up into the better-cooled central portions is condensed long before it reaches the top, the passages and air above it being kept cold by the fan. The uplowing steam can push the air upward only the limited height to which such steam rises before being condensed.

As a result there remains in the central portion of the radiator a body of air which is supported from below by up-tlowing steam and sealed in above by steam risin from the sides. Reverse curl or eddying o such steam from the sides may serve to scavenge out more or less offthe air in the relatively open .space above the honeycomb, but has practically no effect on the' air trapped and kept cold in the narrow central passages of the radiator. Hence the air thus trapped stays trapped, ,practically excluding the steam which mightotherwise flow in from both top and bottom. l

While this objectionable action may be more readily 4analyzed and understood in connection with radiators of the type in which the steam passages are parallel vertical conduits having no cross flow connections except at top and bottom, nevertheless. the same action is found to occur to an undesirable extent in radiators of the type in whichthe honeycomb is built up from a multiplicity of short horizontal tubes forming .an interconnected net-work of passages and cross-connections. Y

In its broadest aspects, my invention insteam condensing passages with reference to lthe different portions of the area fof the radiator so that the steam will flow through all of the condenser passages at rates which will insure driving the contained air to a point suitable for its collection and discharge instead of' trapping it. i

The preferred point for collection and discharge of the air is the upper. space in the radiator above the top of vthe...condensing 1 passages. To drive it therelafrrange matters so that steam will not reach the well cooled central portions of the radiator except from below. There are many factors, one or more of which may be varied sepa- 1 rately or together to bring about this result.

The up-ilow paths at the sides may have their flow capacity decreased. This maybe accomplished by making them longer, or o f smaller cross-section, or arranging them so that the flowing steam will be checked by a succession of high-angled impacts, all of which factors are utilized in the device of my rior application, Serial Number 500,- 382 led Se tember 13, 1921, patented May 15, 1923, o. 1,455,737. The decrease of flow section and the obstruction by impact may be distributed from bottom to top of the side passages as in said application, or mty be localized at desired points.

or radiators of the type in which the radiating elements consists of `vertical tubes arranged to afford separate parallel paths for flow of the steam, a similar 4result may be accomplished by having an obstruction, preferably at the upper ends of the side tubes, thereby increasing the flow resistance at said upper ends.

The obstruction may be\any desired form of local constriction, preferably a closure with a vent through it. The vent may be very small, because proper `functioning requires only an extremely small flow capacity at this point, merely sufficient to permit slow in and out hreathin in response to variations of height to which the steam has to rise in the tubes before it is condensed. A vent suiciently large for this pur ose, may yet be small enough to afford relatively enormous throttling resistance to outrush of steam in uantities such as would cause down-flow 1n the central tubes.

Where the tubes are large, say J@to 1%, inch in internal diameter, it may prove convenient to have a separate vented closure in the upper end of each side tube, but, if desired, a single closure may be fitted over the ends of several adjacent tubes, in which case a single vent is used for each closure. Thus the vent may be proportionally larger vfor a given resistance. Such oup arrangement is particularly desira le where the tubes are of such small diameter that control of each by a arate vent would reuire a vent so smal that it would be in an er of gettin clogged.

e .size of t e vent is preferably such that the volume of steam escaping vfrom the tops of the side tubes will be kept well below the condensing capacity of the top space, until and except when the steam evolution in the base of the radiator becomes great enough to bring the steam to the tops of the best cooled central tubes. The radiating capacity of said space may be increased. as by making the same a secondary minature radiator, preferably of the cross-tube type.

I may obstruct and vent all of the tubes in the radiator on the general principle' that, if any of the tubes are deficient in condensing capacity as compared with other tubes, the obstruction and vent therein. will prevent the outow of sufcient steam` to exceed the condensing capacity of the upper chamber or to cause air trappin downlow in any or many of the other tu es.`

The above and other features of my invention will be more fully understood from the following description in connection with the drawings, in which,

Fig. 1 is a front elevation partly in vertical section showing one form of my in-v vention as embodied in a radiator of the vertical tube type.

Fig. 2 is a plan view of a horizontal set,-Y tion on the broken line 2 2, Fig. 1. y

Fig. 3 is an enlarged detail in vertical section on the line 3 3, Fig. 2.

Fig. 4 is a vertical sectional elevation showing a modification.

Fig. 5 is a top plan view in 'horizontal section on the broken line 5 5, Fig. 4.

Fig. 6 is a vertical sectional detail of a modification taken on a line corresponding to line 6 6, Fig. 5. l

Fig. `7 is an elevation artly in section, and Fig. 8 a detailed vertical section showing another modification.

It will be understood that the radiators as shown in these drawings are of the air cooled type, and adapted for use in combination with the motor, water supply system, pump and fan commonly employed'on automotive vehicles. They may be,` and preferably are, units adapted to be substituted for the radiator 4, in the combination of parts shown in Fig. 1 of my abovementioned patent; but they may be employed wit or without modifications, wherever an equal-flow up-low, or air scavenging condenser is desired.

In Fig. 1 ofthe present drawings, the radiator, here used as a condenser, com rises the separating chamber 1 into whic the steam or hot water and steam from the engine is discharged 'through ipe 2. The water, including condensate, ows out of said space through pipe 3, preferably drawn by a pump which is preferably a force pump and may be a gear pump, as shown in my said patent.

From the separating chamber extend parallel-related tubes, as 4, 4, 4", and 4", communicating at their upper ends with. the space 5 at the top of the radiator. Assuming that the structure shown'is of the full size commonly employed on trucks, the tubes 4 may be, say 24 inches high and in diameter, l inch to ys inch, or of much smaller diameter, as on some automobiles. In practice, there may be many more of them than are shown in the drawings.

Said parallel tubes are secured in thin transverse plates 6, 6, the primary function' of which is to conduct and radiate heat from the walls of the tubes, although they also afford some protection and lateral.E support,

'tendirff "to hole the tubes in properly space-: Y

relaties. The ends of the tunes are soldered,

rasee losses.

As previously explained, the tubes at-the sides are not so well supplied with air draft by the fan and hence arr.- not so well cooled as are the central tubes. The normal result of this would be for -the steam to exceed the condensing capacity ofthe side tubes, and rise into space 5; while a similar volume of steam owing .into the central tubes would be full condensed in the lower part thereof. The o ctions for lpreventing this are shown in Figs. 1, 2, an 3, as alforded by a plug 9 in the upset end of each tube, each plug being provl ed with a vent 10 of suitable length and diameter. All of the tubes are shown as similarly plugged and vented on the general principle that the vents afford no serious obstruction to slow breathing, yet will throttle excessive outrush of steam from any tube that may be or become deficient in radiating capacity as compared with other tubes, but I tlnd that equipping the side tubes only is suicient, and therefore preferable.

While the sizes of the vents mayx be gradi' uated to correspond with the condensing etliciency of each separate tube, this is not n ma: ry and a few sizes, or a single, properly selected size, may be used with good results. i

The tubes being all supplied with steam at the same pressure, the sizes of the vents required for the side tubes will depend primarily upon the flow resistances o the several tubes. Where the tubes are all of the same flow resistance, as in the present case, the vent must be small enough size or great enough len h so that, after v the air has been gradua ly l:felled from the side tubes, as above descri ow out of their to s, the flow resistance at the vent will be s cient to pile up a slight back pressure. Such back pressure necessarily takes eect as an upward pressure in the central' tubes. Such upward pressure from the side tubes as 4" must be suicient for establishing and maintaining the large volume of flow of steam which the central tubes, such as 4*, will sustain by reason'of its greater condensing capacit per unit area of cooling surface, and, in a dition, the excess pressure necessary to lift the' heavy cool air in the upper parts of a central tube 4. This air, as we have seen, is a fluid which is naturall some heavier than the steam which lille the side tube 4*, and, in the present case, said air has 20% or so additional weight because it is kept nearly at atmospheric temperature by the direct blast of the and live steam begins to fan, as against the boiling temperature of the live steam 'in the side tubes, 4".

The greater the condensing capacity of the top space 5, the greater may be the volume of steam`vthat may be permitted to escape from the side tubes without material impairment to functioning. Hence I preferablyl rovide the casin of the upper space wit eat radiating ri 11, 11, and vif desired, with transverse air tubes 12, 12. A group of thesefcross tubes 12\,is shown as centrally located and will be recognized as constituting a miniature condenser of the cross-tube, or honeycomb,- type.

I find that locating the,restr1ctions at the tops of the side tubes, has advanta over locating them at ony other point in 5?; tube, and also over making the side tubes of uniform smaller flow-section throughout their length One advantage is tha;L the downflow of condensatev is less retarfled by the up-tlowing steam.

The modifications shown in Figs. 4, 5, and

6 will be readilyunderstoodfrom the above full description of the forms shown in Figs. 1, 2, and 3. In the modifications, a single closure and vent for each group of adjacent tubes, instead of for each tube, is provided. This arrangement is particularly adapted for radiators in which the vertical tubes'are greatly multiplied in number and correspondingly reduced in diameter. In such radiators very thin-walled, copper tubes, having ardiameter of 1/4 inch or less, are

commonly employed. While such tubes could conveniently be supplied with individual constrictions at their tops, it is evident that a single closure and vent for a group of tubes will be less expensive to manufacture and the vent may be'preportionally larger so that it is less liable to become choked with scale, sediment or dirt.v The yvent needs to be small only in relation to the combined cross-sectional'areas of Yall of the tubes of thegroup and need only be small enough to limit free flow of steam from the tops of the less cooled groups and to establish the slight back pressure which will force into the central tubes, thefrela-l tively large volume of steam necessary to utilize their superior condensing capacities: and to do so with force sutlicient to lift and expel the heavy cool air in the central and upper portions of said central tubes.

In Fig. 4, the vertical tubes are comprised in four groups of which the side groups are controlled by caps 9, 9', having vents 10, 10': .and the central groups by caps 9", 9' having vents 10", 10". As before stated,there may be a greater or less number of individual groups and caps and.if desired, only the side groups need bev capped. the central ups remaining unobstructed.

`Another feature shown in Fig. 4 is having the over-flow pipe 13` arranged with its intake .located near the bottom of upper space 5. This arrangement is .of advantage, b ecause when steam escapes from the to s of the side tubes in any substantial vo ume, and there begins to be a slight pressure to cause out-flow through 13, the iiuid that Hows out will be the downwardly displaced heavy air rather than the steam which naturally seeks the top of said space 5. f

It will be noted that the vents 10" do not leadfrm the lowest point in space 5; hence space 5 will not be completely drained of condensate. This may be of no great importance -in someclimates and under oertain conditions, but where complete drainage of condensate is desired, the vents may be arranged after the manner shown in Fig. 6. Here the groups arepclosed in by plate 30, having separate cavities 31, 31, for each group of tubes. The upper surface of the plate is formed as shown so that all condensate will drain by gravity toward the downwardly directed vent 10x.

In the foregoing I have referred to the tubes which are less cooled and which require restriction of their How capacity as being the side tubes, and those which are better cooled and more likely to trap air as being the central tubes. It will be'evident, however, that in attempting to apply my invention to radiators other than those illustreatedherein, it will always be a question of fact which tubes have y.excessive flow capacity or deficient-cooling.

For instance, a vertical tube radiator may have so many banks of tubes from front to rear and these tubes may be so thin walled and closely set that rear tubes may be insufficiently cooled as compared with the front tubes. In such case the rear tubes have their How capacity restricted.

Figs. 7 and 8 indicate a simple arrangementv wherein two vented partitions are employed on the so-called cellular type of radiator. In this type, the up-and-down passages a'ord separate parallel paths for flow of 'steam and condensate, but each flow path follows vertical and horizontal directions alternately, as by following three sides of successive rectangles. These zig-zag passages are commonly formed by two sheets of thin brass or copper of the desired length, folded together and soldered atthe edges to form flat tubular strips, having a cross section, say three to three and one-half inches from front to rear of the radiator, but in thickness only one-sixteenth inch to onethirty-second inch, or less. The present arrangement will be recognized as another solution of the problem presented in my application, Serial Number 500,382, filed Septelnber 13, 1921, patented May 15, 1923` No. 1,455,737.

In my present arrangement, the honeycomb construction is uniform` throughout,

but the corners of the honeycomb aresliced olf so that, while the central flow passages 14a are all of the same length andhe'ight, the passages 14h! are progressively shorter toward the respective sides. Such radiators are standard equipment on Crane-Simplex automobiles. This radiator, in original form,

when connected for operation in accord-l ance with my steam cooling method, gave marked indications of the above-described premature rush of steam through the shorter side passages and a cold spot due-to trapping of air at the upper central portions of the honeycomb.

This radiator was. then equipped with two partitions 19, 19", one on each side, shutting off the outlets of the side tubes which are shorter and farther removed from the cooling draft produced by the fan. In each partition is a vent 10. This arrangement works well when the diameter of the vents is, say one-eighth of an inch to one-sixteenth of an inch, or even less. When the diameter is one-eighth of an inch and the engine is working at full load, there seems to be enough steam from the vents to .heat up the space in the top of the reservoir, but the steam coming through the vents is insufllcient to trap air in the central portion. The central portion heats up clear to thef top and all over before any steam blows ofi'.I -While advantage may be derived. fromvpar- In the last described arrangement whereinA the empty space in the top ofthe radiator is provided with vented partitions, as well as in all other herein described forms .ofthe invention, the vented restrictions have been referred to as being interposed between the vertical tubes and said"empty space. As to this, it is important to note that said empty space is an equal-pressure cross connection between the vents of the tubes and the atmosphere. It follows that in certain cases the open air may be substituted for said empty space and that, if the vents are properly proportioned, they may haveV their pressure cross-communication through the open air. Either with or without said empty space, the vents leading to the open air may be controlled bv valves if desired. F or instance, out-breathing check valves may be arranged 'for every vent; or in-breatliing valves for some vents and out; breathing valves for others. Preferabl such valves .will be very light, particular y the out-breathing valves may be small ball check valves with the ball vmade of bakelite.

It will be recognized that my present inventions concern ways of diverting or shifting the iow of steam to a desired extent' from the radiator passages of less cooling capacity `to those of greater cooling capacity. As concerns the broad invention the arrangements herein shown are closel related to those of my applications, Serial Numbers 500,381 and 500,382, tiled September 13, 1921, and Serial Number 520,209, filed December 6, 1921, patented May 15, 1923, Nos. 1,455,736, 1,455,737, and 1,455,738. The present case is selected for presentation of the generic claims, the intention being to present in the other applications claims which cannot be made in this application.

I claim:

1. A radiator embod ing separate interior passages for up-flow o steam or vapor to be condensed; means including a cross communication between the lower portion of said paages for up-low supply of steam or vapor to said passages, some of the flowy paths normall having greater cooling capacity than oters; portions of the iow section which have less condensing capacity being arra d to have less flow capacity than those aving greater condensing capacity.

2. A radiator comprising a lower chamber and an upper chamber and separate intermediate through sai lower and .upper chambers; means for supplying steam in said lower chamber and withdrawing condensate therefrom and means whereby air may breathe in and out'of said upper chamber to relieve excessive internal pressure and vacuum conditions attendant upon use of the device, the

' pa of less condensing capacity having greater flow resistance than those of greater condensing capacity.

3. A radiator comprising a lower chamber and an upper chamber and a multiplicity of separate intermediate passa es cross-commumcating only through said ower and uppcr chambers; means for supplying steam in said lower chamber and wit drawing condensate therefrom and means for permitting air to breathe in and out of said upper chamber in response to the internal pressure attendant upon use of .the device, certain of said passages being of similar flow section but less length than others in comlp binatidn with means for obstructing out-flow of steam from said shorter passages.

4. A radiator of the `type comp'ising a lowerv chamber and an upper cham r and a multiplicity of separate intermediate pastpassages cross-communicating.

sages cross-communicating only through said lower and upper chambers; means for su plying steam in said lower space and wi rawing condensate therefrom and means for permitting air to breathe in and out of said upper space 'in res onse to the internal pressure changes atten ant upon use of the device, certain of said passages being of similar ow section but of less length than others in combination with vented outlets for said shorter pasages to ermit slow in and out breathin of air w ile throttling outrush of steam rom said shorter passages when their radiating capacit is overtaxed. 5. A variable-duty, air-coo. ed radiator of the type comprising a lowerspace connected by a multiplicity of upwardly extending tubes with an upper space; means for discharging boiling liquid or steam into said lower space and for 'withdrawing condensate therefrom; and a desired. number of restrictions controlling outlet of steam from the upper ends of a desired number of said tubes. l u v 6. A variable-duty, air-cooled radiator of the type comprising va lower chamber connected by many upwardly extending tubes with an upper space for escape of air means for discharging boilin liquid or steam into said lower space and or withdrawing condeiisate therefrom; and a desired number of vented outlets each controlling outlet of steam from'the upper end of a.y different group of tubes.

7. A variable-duty, air-cooled radiator of the type comprising a lower cross-connection communicating Vwith man upwardly extending tubes; means for ischarging boiling liquid or steam into said lower cross-.connection and for withdrawi condensate therefrom; and a desired num r of vented outlets, each controlling outlet of steam or vapor from the upper end of a diilerent group of tubes, the tubes being grouped for similarity of condensing capacities.

8. A variable-duty, air-cooled radiator of the type comprising a lower space connected by a multiplicity of upwardly extending tubes with anupper space accessible to air; means for discharging boiling liquid or steam into said lower space and for withdrawing condensate-therefrom; and one or more vented outlets, each controlling outlet of steam or vappgr from the upper ends of a group of tu having lesser condensing capacity'.

9. A radiator in which the interior paths for ow -of steam or vapor to be cooled are laterally distributed and some ofthe How aths normally have greater cooling capacity than others, and are arranged to permit escape of air through .the upper portions thereof, in combination with connections for operating ysaid radiator as an up-flow condenser; portions of the ow section-having Aais severalpassages, and by v. coolingl less condensin capacity being arranged have less flow t an those having greater condensin capacit Y 10. variable-duty, air-cooled radiator in which the interior paths for dflow of fluid to be cooled are 'laterally distributed and some of the How paths rnormally have greater capacity than others and are arto permit esca e of air through the upper portions thereo in combination with means for up-iiow su ply of steam or vapor to interior paths of dlilerent cooling capacities simultanecusl and at approximately equal pressures; se ected portions of the flow section of lesser -condensing capacities being arranged to have correspondingly greater iiow resistance whereby other portions having greater condensing capacities are adequatel supplied with steam or vapor before said rst-mentioned portions are overtaxed enough to permit excessive through-flow of the steam or vapor.

11. An air-cooledradiator in which the Iinterior aths for How of duid to be cooled are latera y distributed, andI some of the flow aths have less cooliii .capacity per unit ength than others; an means for supplying said fluid thereto from a common source simultaneously and at approximately the same'pressiires portions of the How section having less coo n capacity being arranged to have correspon ing y greater flow resistance than those having greater cooling capacity; for the purpose and 'vith the result that the fluid automatically distributes its flow according to theseveral cooling capacities.

12. A variable-dut radiator havingmany` interior paths of di erent cooling capacities y or rates;means for up-flowsupp y of steam or vapor to many of said interior paths simultaneously at approximately equal pressures, whereby air within the radiator automatically forced by the fiow of the steam or vapor to a region determined by the volume of said flow, -by the several ow capacities and condensingl capacities of the t e superior weiglit of the air; in combination zvith flow restricting means for limiting Vthe free How of steam from the less actively cooled passages into said region.

13; A variable-du y, air-cooled radiator of a type having many interior paths of different cooling capacities or rates; means for lip-flow supply of steam or vapor to many of said interior paths, simultaneously, whereby, as the volume of steam increases, air within the radiator is `automatically forced by the flow of the steam or va or to a region determined b the volume o said How, by the several ow capacities and condensing capacities of the several passages, and by the superior weight ofK the air; in combination 7with an outlet frein said regidn permitting:

affording front area and thin 'from front to rear andy adapted to be cooled by an induced draft effective unequally on different portions of the front area; said radiator comprising a lowery chamber and an upper chamber connected by many upwardly extending tubes of similar material, cross-section and thickness of walls, cross-communicating only through said lower and upper chambers; means for suppl ing boiling liquid, steam or vapor to all o said tubes simultaneously and at approximatel through/said lower c amber and for withdrawing condensate therefrom; and flow restricting means for imposing predetermined restriction on How of steam or vapor from theupper ends of certain of the tubes which are less effectivelyk cooled than others for the purpose described. l

15. In the combination specified by claim 14, the further feature that the less wellcooled tubes are shorter than otherv tubes and the vents therefor are correspondingly restricted to prevent up-rush of steam or vapor in excess of the radiating capacity of the upper chamber.

16. An air-cooled condensing apparatus interior, laterally distributed, parallel pat s for flow of uid -to be cooled, some of which parallel paths have less cooling capacity than others; and means for supplying said fluid to the parallel paths from a coin'- mon source; certain of the parallel How paths of less cooling capacity being arranged to have substantially greater total ow resistance than those having ygreater cooling capacity; for the purpose and with the result that the fluid automatically fiows in greater quantity to the ow paths havingy greater cooling capacity.

17. An air cooled radiator havin low resistance ow'paths for the cooling uid over the central portions of the area. of the honey comb and higher flow resistance for the paths at the side portions of said area.

18. air cooled condensing radiator of a. type having a plurality of separate con-y densin passages, permitting through ilow of ilui ,and a common source freely supplying steaming duid to all of said passages and in which in operation some of said pasthe saine pressuresA llO sages may /have their condensing capacity overtaxed before other of said passages are operating at maximum condensing capacity, in combination with outlet restricting elements for said passages, said outlet restricting, elements opposing relatively reat How resistance to quantity outow of uid from l,said passages, for the purpose and with the eral coo ing calacities.

result that back pressure is created in said overtaxed passages whereby'said steamingiluid is caused to flow in increased quantity into such of said passages as are not operating at maximum condensing capacity.

19. An air cooled condensing apparatus having interior, 'parallel paths for l'low of fluid, s'ome of which paral el paths have less 'y cooling capacity than others, means for supplyiiig steaming Huid to said parallel pa from acommon source; a chamber into which all of said paths have outlet, and in which apparatus, in operation, the paths of less cooling capacity may become overtaxed and permit through flow of steam before the apparatus as a whole is operating at full conde capacity, in combination with llow restricting elements for said passages. opposing relativel great flow resistance to through flow of uid -for the `purpose and with the result that excessive outrush of steamin fluid .for said passages is prevent.

ed and ack pressure set up in those paths having least coolingl capacity so that the flow of fluid` is automatically distributed according to the cooling capacity of the several passa air-cooled. radiator in which the interior paths for flow of fluid to be cooled -are laterally distributed and some of the ow paths have less cooling capacity per unit lengthI than others; and means for supplying said lluid at the inlet ends of all said paths, from a common source, simultane- `ously and at approximately the same ressures; and a c amber at the outlet en of said paths into which uids may How; and outlet restricting elements designed to afford no serious obstacle to slow outflow of fluid but operating to restrain excessive outrusli. of steam, whereby when in full operation, portions of the flow section having less cooling capacity have correspondingly greateriiow resistance than those having greater cooling capacity; for the purpose and with the result that the iow of'steam is,auto maticall distributedaccording to the sev.-

of the motor 21.- A variab -duty radiator front vehicle type which is of relatively lar area and thin from front to rear an ed to be cooled by an induced draft e ective unequally at diiferent portions of the front area, 'said radiator includ two `chambers connected through a plura ty of tubes or passages hav' spaces therebetween for the How of air. om front to rear, said tubes crow-communica through said chambers, means for supplying bolin liquid, steam or vapqf through one of sai steam or vapor from said supply chamber through tubes that are less eiectively cooled,

to the other chamber and into the outlet ends of the more effectively cooled tubes trap air in the latter.

22. A variable-duty'radiator of the motor vehicle type which is of relatively large front area and thin from front to rear and adapted to be coled by an induced draft effective unequally at di'erent ortions of the front area, said radiator inc uding two chambers connected through a plurality of 23. A variable-duty radiator of the mo-I v tor vehicle type which is of relatively large front area' and thin from front to rear and adapted to be cooled b an induced draft efectivo unequally at 'ferent portions of the front area, said radiator having a pair of chambers connected by a plurality of tubes having s aces therebetween for the flow of air om .front to rear, said tubes cross-communicating only through said chambers, means'for supplying boiling liquid, steam or vapor to all of said tubes simultaneously and at approximately the same pressures through one of said chambers, and flow retarding meas'for a reventing steam from the less actively coo ed passages from enterin the outlet ends'of the more actively cool air in the latter.

24. A radiator of the motor vehicle type which is of relatively large front area and thin from front to rear and adapted to be cooled by an induced draft ofair from the front to the rear, said radiator includin a pair of chambers connected by a pluraty of substantially parallel tubes, means for sulpplying boiling liquid, steam or vapor, to al of said tubes-simultaneously, andy at ap- `proxiiiiately the same pressures through one of said chambers, a partition subdividing the otherchamber into compartments havin restricted communicationl with each ot er, and an air outlet communicating with one of said compartments.

25. A radiator of the motor vehicle type which is ofrelatively large front area and thin from front to rear and adaptedcto be cooled by an induced draft of air from the.

front to the rear, said radiator including chambers connected by a plurality of substantially tubes,rmeans for supplying boilin of said tu s simultaneously, through one of said chambers, and means in the other chamber for separating said tubes into groups having restricted communication with each other through said last mentioned chamber. y

26. A radiator of the motor vehicle type which is of relatively large front area and thin from front to rear and adapted to be cooled by an induced draft of air from the front to the rear, said radiator comprisin a pair of'chambers connected b a plurallty of arallel-tlow tubes, means or supplyinv. boigng liquid, steam or vapor, to all of said tubes simultaneously, and at approximately the same pressures, through one of said chambers, and vent means for certain of said tubes the size of the vent being such that the'volume of steam escaping from the liquid, steam or vapor, to al1.

tubes will bekept well below the condensing capacity of said second mentioned chamber.

27. A variable-duty, air-cooled radiator of the motor vehicle type, including a fluid receiving and di; tributing.. chamber connected by many separate condensing tubes or passages with an outlet space for escape of air; means for discharging boiling liquidV or steam into said chamber; outlet means to permit condensate to leave the radiator; and a desired number of vent outlets, each'controlling outlet of steam or vapor from the SAMUEL W. RUSHMORE. 

